Small doses of aripiprazole augmentation of antidepressant treatment: a report of 3 cases

An investigation into aripiprazole's partial D₂ agonist effects within the dorsolateral prefrontal cortex during working memory in healthy volunteers

RATIONALE

Working memory impairments in schizophrenia have been attributed to dysfunction of the dorsolateral prefrontal cortex (DLPFC) which in turn may be due to low DLPFC dopamine innervation. Conventional antipsychotic drugs block DLPFC D2 receptors, and this may lead to further dysfunction and working memory impairments. Aripiprazole is a D2 receptor partial agonist hypothesised to enhance PFC dopamine functioning, possibly improving working memory.

OBJECTIVES

We probed the implications of the partial D2 receptor agonist actions of aripiprazole within the DLPFC during working memory. Investigations were carried out in healthy volunteers to eliminate confounds of illness or medication status. Aripiprazole's prefrontal actions were compared with the D2/5-HT2A blocker risperidone to separate aripiprazole's unique prefrontal D2 agonist actions from its serotinergic and striatal D2 actions that it shares with risperidone.

METHOD

A double-blind, placebo-controlled, parallel design was implemented. Participants received a single dose of either 5 mg aripiprazole, 1 mg risperidone or placebo before performing the n-back task whilst undergoing fMRI scanning.

RESULTS

Compared with placebo, the aripiprazole group demonstrated enhanced DLPFC activation associated with a trend for improved discriminability (d') and speeded reaction times. In contrast to aripiprazole's neural effects, the risperidone group demonstrated a trend for reduced DLPFC recruitment. Unexpectedly, the risperidone group demonstrated similar effects to aripiprazole on d' and additionally had reduced errors of commission compared with placebo.

CONCLUSION

Aripiprazole has unique DLPFC actions attributed to its prefrontal D2 agonist action. Risperidone's serotinergic action that results in prefrontal dopamine release may have protected against any impairing effects of its prefrontal D2 blockade.

The effectiveness and safety of adjunctive aripiprazole in Taiwanese patients with antidepressant-refractory major depressive disorder: a prospective, open-label trial

There is currently no published clinical trial on the safety and effectiveness of aripiprazole in Taiwanese patients with treatment-refractory major depressive disorder. We were interested in determining the applicability of current recommended doses of aripiprazole as an adjunct to antidepressant therapy in this population. We conducted a prospective, open-label nonrandomized, 4-week flexibly dosed (2.5-5 mg/d) trial with aripiprazole augmentation in 9 Taiwanese patients who had a history of nonresponse to at least 2 adequate courses of antidepressant therapy with different types of antidepressants. The primary end point for clinical effectiveness was mean change in the 17-item Hamilton Rating Scale for Depression at the end of the 4-week trial. Secondary end points for clinical effectiveness included mean change in Beck Depression Inventory and Beck Anxiety Inventory scores. The Systematic Assessment of Treatment Emergent Events-General Inquiry was used to assess adverse effects. All patients completed the trial and responded to treatment; the remission rate was 77.8%. The mean daily dose of adjunctive aripiprazole was 4.2 mg. Common treatment-emergent adverse events included insomnia and sedation (33.3%) and akathisia (22.2%). We found high effectiveness despite a lower mean daily dose of adjunctive aripiprazole (4.2 mg) when compared with previously reported findings; however, we also observed a higher frequency of treatment-emergent adverse effects. Additional studies are required to ascertain whether there are ethnic differences in the pharmacokinetics and/or pharmacodynamics of aripiprazole in treatment-refractory depression.

Adjunctive low-dose aripiprazole with standard-dose sertraline in treating fresh major depressive disorder: a randomized, double-blind, controlled study

OBJECTIVES

Second-generation (atypical) antipsychotics have been accepted as an adjunctive medication in patients with treatment-resistant depression. This clinical trial evaluated the efficacy and safety of low-dose aripiprazole combined with regular-dose sertraline for acute major depressive episode in non-treatment-resistant depression outpatients.

METHODS

The study patients were 18- to 65-year-old outpatients fulfilling the criteria of major depressive disorder in Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. The patients were randomly assigned to 2 groups: one with sertraline 50 mg/d plus aripiprazole 2.5 mg/d and the other with sertraline 50 mg/d plus placebo. After baseline assessment, the subjects were followed up at weeks 1, 2, 4, 6, and 10. The primary efficacy was the score change of the 17-item Hamilton Rating Scale for Depression (HAM-D17), and secondary efficacies were the score of Short Form 36 Health Survey, Clinical Global Impressions-Severity, and Clinical Global Impressions-Improvement. This study also monitored patients for movement disorder using Simpson-Angus Scale and Barnes Akathisia Rating Scale.

RESULTS

Twenty-one patients were assigned to the aripiprazole group and 20 to the placebo group. Because of high dropout rate, only data of the first 4 weeks were analyzed. The aripiprazole group exhibited significantly better efficacy than the placebo group in mean total score changes of HAM-D17 from the baseline to weeks 1, 2, and 4. The item "work and social activities" of HAM-D17 showed significant improvement at week 2, and the item "somatic symptoms (GI)" showed significant improvement at week 1. The aripiprazole group exhibited significant improvement in "social role function" section of Short Form 36 Health Survey at week 4. The mean total score of Clinical Global Impressions-Severity showed marginally significant improvement in the aripiprazole group. In Clinical Global Impressions-Improvement, patients in the aripiprazole group had scores of less than 2 (much improved) at weeks 2 and 4, and the scores of the placebo group were greater than 2.4 (indicating a minimal improvement). No patients had akathisia during the trial period.

CONCLUSIONS

The primitive data showed that adjunctive low-dose aripiprazole could augment the efficacy of regular-dose sertraline in fresh major depressive disorder. A large-scale study is needed to confirm this finding.

Unusual weight fluctuation under corticosteroid and psychotropic treatment

It is generally accepted that corticosteroid therapy may increase weight. Because corticosteroids may induce several psychiatric symptoms, psychotropic drugs are required to treat these symptoms in some cases. The present study describes a patient who had unusual weight fluctuation under corticosteroid and psychotropic treatment such as mianserin and aripiprazole.